Ferromagnetism in diluted magnetic semiconductor quantum dot arrays embedded in semiconductors

TL;DR

This paper models ferromagnetism in diluted magnetic semiconductor quantum dot arrays embedded in semiconductors, highlighting how hybridization and exchange interactions induce long-range magnetic order and spin polarization.

Contribution

It introduces an Anderson-type model with exchange coupling to analyze ferromagnetism in DMS quantum dot arrays, incorporating hybridization effects and using mean field and spin wave approximations.

Findings

Long-range ferromagnetic order can be induced by hole transfer between quantum dots.

Carrier spins in quantum dots and semiconductors become polarized.

Spontaneous magnetization is successfully calculated using developed models.

Abstract

We present an Anderson-type model Hamiltonian with exchange coupling between the localized spins and the confined holes in the quantum dots to study the ferromagnetism in diluted magnetic semiconductor (DMS) quantum dot arrays embedded in semiconductors. The hybridization between the quantum-confined holes in the DMS quantum dots and the itinerant holes in the semiconductor valence band makes hole transfer between quantum dots, which can induce the long range ferromagnetic order of the localized spins. In addition, it makes the carrier spins both in the DMS quantum dots and in the semiconductors polarized. The spontaneous magnetization of the localized spins and the spin polarization of the holes are calculated using both the Weiss mean field approximation and the self-consistent spin wave approximation, which are developed for the present model.